package com.tianji.learning.service.impl;

import com.tianji.api.client.course.CourseClient;
import com.tianji.api.dto.course.CourseFullInfoDTO;
import com.tianji.api.dto.leanring.LearningLessonDTO;
import com.tianji.api.dto.leanring.LearningRecordDTO;
import com.tianji.common.exceptions.BizIllegalException;
import com.tianji.common.exceptions.DbException;
import com.tianji.common.utils.BeanUtils;
import com.tianji.common.utils.UserContext;
import com.tianji.learning.domain.dto.LearningRecordFormDTO;
import com.tianji.learning.domain.po.LearningLesson;
import com.tianji.learning.domain.po.LearningRecord;
import com.tianji.learning.enums.LessonStatus;
import com.tianji.learning.enums.SectionType;
import com.tianji.learning.mapper.LearningRecordMapper;
import com.tianji.learning.service.ILearningLessonService;
import com.tianji.learning.service.ILearningRecordService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.tianji.learning.utils.LearningRecordDelayTaskHandler;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * <p>
 * 学习记录表 服务实现类
 * </p>
 *
 * @author author
 * @since 2025-01-18
 */
@Slf4j
@RequiredArgsConstructor
@Service
public class LearningRecordServiceImpl extends ServiceImpl<LearningRecordMapper, LearningRecord> implements ILearningRecordService {

    private final ILearningLessonService lessonService;
    private final CourseClient courseClient;
    private final LearningRecordDelayTaskHandler taskHandler;

    /**
     * 查询当前用户指定课程的学习进度
     * @param courseId
     * @return
     */
    @Override
    public LearningLessonDTO queryLearningRecordByCourse(Long courseId) {
        //1.获取用户id
        Long userId = UserContext.getUser();

        //2.查询课表信息 条件user_id  course_id
        LearningLesson lesson = lessonService.lambdaQuery()
                .eq(LearningLesson::getUserId, userId)
                .eq(LearningLesson::getCourseId, courseId)
                .one();
        if (lesson==null){
            throw new BizIllegalException("该课程未加入课表");
        }

        //3.查询学习记录 条件user_id  lesson_id
        List<LearningRecord> recordList = this.lambdaQuery()
                .eq(LearningRecord::getLessonId, lesson.getId())
                .eq(LearningRecord::getUserId, userId)
                .list();

        //4.封装结果返回
        LearningLessonDTO dto = new LearningLessonDTO();
        dto.setId(lesson.getId());
        dto.setLatestSectionId(lesson.getLatestSectionId());
        List<LearningRecordDTO> dtoList = BeanUtils.copyList(recordList, LearningRecordDTO.class);
        dto.setRecords(dtoList);
        return dto;
    }


    /**
     * 提交学习记录
     * @param dto
     */
    @Override
    public void addLearningRecord(LearningRecordFormDTO dto) {
        //1.获取用户id
        Long userId = UserContext.getUser();

        //2.处理学习记录
        boolean isFinished = false; //代表本小节是否已学完
        if (dto.getSectionType().equals(SectionType.VIDEO)){
            //2.1提交视频播放记录
            isFinished = handleVideoRecord(userId, dto);
        }else{
            //2.2提交考试记录
            isFinished = handleExamRecord(userId,dto);
        }

        //3.处理课表记录
        if (!isFinished){ //如果本小节不是第一次学完，不用处理课表数据
            return;
        }
        handleLessonData(dto);


    }

    /**
     * 处理课表
     * @param dto
     * @param
     */
    private void handleLessonData(LearningRecordFormDTO dto) {
        //1.查询课表 learning_lesson  条件lesson_id
        LearningLesson lesson = lessonService.getById(dto.getLessonId());
        if (lesson == null){
            throw new BizIllegalException("课表不存在");
        }

        //2.判断是否第一次学完  isFinished是不是true
        boolean allFinished = false;

        //3.远程调用课程服务，得到课程信息（小节总数）
        CourseFullInfoDTO cinfo = courseClient.getCourseInfoById(lesson.getCourseId(), false, false);
        if (cinfo == null) {
            throw new BizIllegalException("课程不存在");
        }
        Integer sectionNum = cinfo.getSectionNum();//课程小节总数

        //4.如果isFinished为true，本小节第一次学完  判断该用户在该课程下全部小节是否学完
        Integer learnedSections = lesson.getLearnedSections(); //已学小节数
        allFinished = learnedSections + 1 >= sectionNum;

        //5.更新课表数据
        lessonService.lambdaUpdate()
                .set(lesson.getStatus() == LessonStatus.NOT_BEGIN, LearningLesson::getStatus, LessonStatus.LEARNING)
                .set(allFinished, LearningLesson::getStatus, LessonStatus.FINISHED)
                .set(LearningLesson::getLatestSectionId, dto.getSectionId())
                .set(LearningLesson::getLatestLearnTime, dto.getCommitTime())
                //.set(LearningLesson::getLearnedSections, lesson.getLearnedSections()+1)
                .setSql("learned_sections = learned_sections + 1")
                .eq(LearningLesson::getId,lesson.getId())
                .update();
    }


    /**
     * 处理视频播放记录
     * @param userId
     * @param dto
     * @return
     */
    private boolean handleVideoRecord(Long userId, LearningRecordFormDTO dto) {
        //1.查询旧的学习记录 learning_record  条件user_id  lesson_id section_id
        LearningRecord learningRecord = queryOldRecord(dto.getLessonId(),dto.getSectionId());
//        LearningRecord learningRecord = this.lambdaQuery()
//                .eq(LearningRecord::getLessonId, dto.getLessonId())
//                .eq(LearningRecord::getSectionId, dto.getSectionId())
//                .one();

        //2.判断是否存在
        if (learningRecord==null){
            //3.如果不存在 新增学习记录
            LearningRecord record = BeanUtils.copyBean(dto, LearningRecord.class);
            record.setUserId(userId);

            boolean result = this.save(record);
            if (!result){
                throw new DbException("新增考试记录失败");
            }
            return false;
        }

        //4.如果存在  更新学习记录 learning_record  跟新moment
        //判断本小节是否第一次学完 isFinished= ture为第一次学完
        boolean isFinished = !learningRecord.getFinished() && dto.getMoment()*2 >= dto.getDuration();
        if (!isFinished){
            LearningRecord record = new LearningRecord();
            record.setLessonId(dto.getLessonId());
            record.setSectionId(dto.getSectionId());
            record.setMoment(dto.getMoment());
            record.setFinished(learningRecord.getFinished());
            record.setId(learningRecord.getId());
            taskHandler.addLearningRecordTask(record);
            return false;
        }

        boolean result = this.lambdaUpdate()
                .set(LearningRecord::getMoment, dto.getMoment())
                .set(isFinished, LearningRecord::getFinished, true)
                .set(isFinished, LearningRecord::getFinishTime, dto.getCommitTime())
                .eq(LearningRecord::getId, learningRecord.getId())
                .update();
        if(!result){
            throw new DbException("更新学习记录失败！");
        }

        //清理redis缓存
        taskHandler.cleanRecordCache(dto.getLessonId(), dto.getSectionId());

        return true;
    }

    private LearningRecord queryOldRecord(Long lessonId, Long sectionId) {
        //1.查询缓存
        LearningRecord cache = taskHandler.readRecordCache(lessonId, sectionId);

        //2.如果命中，直接返回
        if (cache != null){
            return cache;
        }

        //3.如果未命中，查询db
        LearningRecord dbRecord = this.lambdaQuery()
                .eq(LearningRecord::getLessonId, lessonId)
                .eq(LearningRecord::getSectionId,sectionId)
                .one();

        if (dbRecord==null){
            return null;
        }

        //4.放入缓存
        taskHandler.writeRecordCache(dbRecord);
        return dbRecord;
    }

    /**
     * 处理考试记录
     * @param userId
     * @param dto
     * @return
     */
    private boolean handleExamRecord(Long userId, LearningRecordFormDTO dto) {
        //1.dto转po
        LearningRecord record = BeanUtils.copyBean(dto, LearningRecord.class);
        record.setUserId(userId);
        record.setFinished(true);//提交考试记录，代表已学完
        record.setFinishTime(dto.getCommitTime());

        //保存学习记录learning_record
        boolean result = this.save(record);
        if (!result){
            throw new DbException("新增考试记录失败");
        }
        return true;
    }
}
